/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.lucene.spatial.distance;

import org.apache.lucene.index.IndexReader;

import java.io.IOException;
import java.util.BitSet;
import java.util.Collections;
import java.util.Map;

/**
 * Implementation of {@link DistanceFilter} that does no actual filtering.  This means that there can always be a DistanceFilter
 * instantiated, but that the actual process of filtering documents by their distance, which is a computationally expensive
 * process, doesn't always have to occur.
 */
public class NoOpDistanceFilter implements DistanceFilter {

  private Map<Integer, Double> distancesById = Collections.EMPTY_MAP;

  /**
   * {@inheritDoc}
   */
  public Map<Integer, Double> getDistances() {
    return distancesById;
  }

  /**
   * {@inheritDoc}
   */
  public Double getDistance(int docId) {
    return distancesById.get(docId);
  }

  /**
   * Executes no filtering.  Simply returns the given BitSet
   * <p/>
   * {@inheritDoc}
   */
  public BitSet bits(IndexReader reader, BitSet bits) throws IOException {
    return bits;
  }
}
